Novel members and germline polymorphisms in the human T-cell receptor Vb6 family

The human T-cell receptor (Tcr) Vb6 family has been scrutinized for polymorphisms, both in coding as well as in intronic sequences by polymerase chain reaction (PCR), subsequent multiple electroblot hybridizations, and sequence analysis. Multiplex PCR is an efficient means of screening for Tcr variability. Four novel loci could be distinguished and several new alleles are described including two pseudogenes. The Vb6 family is characterized by an intronic stretch of simple repetitive (gt)_n sequences. These elements are hypervariable, especially in the Vb6.7 subfamily, where they are particularly long. The unexpected persistence of simple repetitive sequences in Tcr and major histocompatibility complex (MHC) class II genes over extended periods of the vertebrate evolutionary history can be interpreted in parallel terms in both gene families.The nucleotide sequence data reported in this paper have been submitted to the nucleotide sequence database GenBank and have been assigned the accession numbers M97503–97505.     

Exonic polymorphism vs intronic simple repeat hypervariability in MHC-DRB genes

Gene products encoded by the major histocompatibility complex often exhibit a high degree of polymorphism. In humans the HLA-DR polymorphism is due to more than 50 alleles with varying exon 2 sequences. Each group of DRB alleles contains a certain form of the basic simple repeat motif (gt)_n(ga)_m in intron 2. Identical alleles can be differentiated on the basis of the hypervariable repeat. In this study focused on cattle (Bos taurus) we identified different Bota-DRB alleles in a limited survey by amplification via polymerase chain reaction and sequencing. In addition DRB exon 2 sequences were also obtained from eight additional hoofed animal species (seven horned artiodactyls and one pig) revealing artiodactyl-specific polymorphic and nonpolymorphic substitutions. In the genus Bos the intronic simple repeat variability was compared with exonic DRB polymorphism. As in humans all Bota-DRB exons were always associated with specifically organized basic simple repeat structures. Yet the extent of simple repeat variability was lower in cattle compared to humans. Selective breeding in the process of domestication might be responsible for the diminished intronic hypervariability. Nevertheless, the hypermutable simple repeat sequences have been preserved in the same position and with the same principal structure for at least 70 × 10⁶ years of evolution. Unexpectedly, the rate of intronic simple repeat and exonic changes appear quite similar.     

Polymorphism and phylogeny of dinucleotide repeats in human T-cell receptor Vb6 genes

The Vb6 subfamily is the largest reported subfamily of human T-cell receptor (Tcr) genes with as many as 14 possible members based on variation in reported DNA sequences. A study of the genomic organization of four distinct Vb6 genes indicated that they contained within their introns theuniterrupted dinucleotide repeat (GT)_n, with n>8. DNA amplification primers and conditions were determined which amplified the intron of these four different Vb6 gene segments. All four Vb6 genes tested showed length polymorphism when examined in a group of unrelated individuals. Careful sizing and DNA sequencing showed that the alleles of each gene differed in size by multiples of two base pairs (bp), due to different repeat numbers of the dinucleotide (GT)_n. These four microsatellite polymorphisms had from three to ten alleles, and individual heterozygosities of 26% to 83%. The large number of alleles and the high heterozygosity make these polymerase chain reaction (PCR)-based polymorphisms very attractive genetic markers for segregation studies which postulate the presence of autoimmune susceptibility genes within the Tcrb region. Vb6 hybridization to genomic DNA confirmed the relatively large size of the Vb6 subfamily in several hominoid species. Nucleotide sequencing of an intron of the Vb6 genes from other primates revealed the presence of dinucleotide repeats similar to those found in human Vb6 genes. Thus, the (GT)_n microsatellite was not only present in the Vb6 intron before Vb6 gene duplication, but was present before speciation of the hominoids.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession numbers L07638, L07640, and X07641.     

Conservation of intronic minisatellite polymorphisms in the SCK1/SHC2 gene of Hominidae

The neuronally expressed Shc adaptor homolog SCK1/SHC2 gene contains an unusually high number of minisatellites. In humans, twelve different minisatellite sequences are located in introns of SCK1/SHC2 and ten of them are highly polymorphic. Here we used primers developed for humans to screen ten intronic loci of SCK1/SHC2 in chimpanzee and gorilla, and undertook a comprehensive analysis of the genomic sequence to address the evolutionary events driving these variable repeats. All ten loci amplified in chimpanzee and gorilla contained hypervariable and low-variability minisatellites. The human polymorphic locus TR1 was monomorphic in chimpanzee and gorilla, but we detected polymorphic alleles in these apes for the human monomorphic TR7 locus. When we examined the repeat size among these hominoids, there was no consistent variation by length from humans to great apes. In spite of the inconsistent evolutionary dynamics in repeat length variation, exon 16 was highly conserved between humans and great apes. These results suggest that non-coding intronic minisatellites do not show a consistent evolutionary paradigm but evolved with different patterns among each minisatellite locus. These findings provide important insight for minisatellite conservation during hominoid evolution.     

Hypervariability of intronic simple (gt)n(ga)m repeats in HLA-DRB genes

We have investigated the extent of DNA variability in intronic simple (gt)_n(ga)_m repeat sequences and correlated this to sequence polymorphisms in the flanking exon 2 of HLA-DRB genes. The polymerase chain reaction (PCR) was used to amplify a DNA fragment containing exon 2 and the repeat region of intron 2. The PCR products were separated on sequencing gels in order to demonstrate length hypervariability of the (gt)_n(ga)_m repeats. In a parallel experiment, the PCR products were cloned and sequenced (each exon 2 plus adjacent simple repeats) to characterize the simple repeats in relation to the HLA-DRB sequences. In a panel of 25 DRB1, DRB4, and DRB5 alleles new sequences were not detected. Restriction fragment length polymorphism (RFLP) subtyping of serologically defined haplotypes corresponds to translated DNA sequences in 85% of the cases, the exceptions involving unusual DR/DQ combinations. Many identical DRB1 alleles can be distinguished on the basis of their adjacent simple repeats. We found group-specific organization of the repeats: the DRw52 supergroup repeats differ from those of DRB1*0101, DRB4*0101, and DRB5*0101 alleles and from those of pseudogenes. Finally, we amplified baboon DNA and found a DRB allele with extensive similarity to DRB1 sequences of the DRw52 supergroup. The simple repeat of the baboon gene, however, resembles that of human pseudogenes. In addition to further subtyping, the parallel study of polymorphic protein and hypervariable DNA alleles may allow conclusions to be drawn on the relationships between the DRB genes and perhaps also on the theory of trans-species evolution.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession number M 34258.     

The paradox of MHC-DRB exon/intron evolution: α-helix and β-sheet encoding regions diverge while hypervariable intronic simple repeats coevolve with β-sheet codons

Twenty-one different caprine and 13 ovine MHC-DRB exon 2 sequences were determined including part of the adjacent introns containing simple repetitive (gt)_n(ga)_m elements. The positions for highly polymorphic DRB amino acids vary slightly among ungulates and other mammals. From man and mouse to ungulates the basic (gt)_n(ga)_m structure is fixed in evolution for 7 × 10⁷ years whereas ample variations exist in the tandem (gt)_n and (ga)_m dinucleotides and especially their degenerated derivatives. Phylogenetic trees for the -helices and -pleated sheets of the ungulate DRB sequences suggest different evolutionary histories. In hoofed animals as well as in humans DRB -sheet encoding sequences and adjacent intronic repeats can be assembled into virtually identical groups suggesting coevolution of noncoding as well as coding DNA. In contrast a-helices and C-terminal parts of the first DRB domain evolve distinctly. In the absence of a defined mechanism causing specific, site-directed mutations, double-recombination or gene-conversion-like events would readily explain this fact. The role of the intronic simple (gt)_n(ga)_m repeat is discussed with respect to these genetic exchange mechanisms during evolution.     

Postcranial morphology and locomotion of the Eocene raoellid Indohyus (Artiodactyla: Mammalia)

Raoellids are small, raccoon-sized Eocene artiodactyls, closely related to archaic cetaceans (archaeocetes) that have poor representation of postcranial elements in the fossil record. Little is known of the aquatic and terrestrial locomotor affinities of raoellids due to the paucity of their fossil record, leaving a critical gap in our understanding of the earliest portion of the artiodactyl marine invasion. To address this gap, a comparative morphological analysis of the postcranial elements was undertaken based on newly recovered elements of the raoellid Indohyus, archaeocetes and extant artiodactyls. Greater than 200 postcranial elements of Indohyus were described, and some limb element cross-sections were visualised via paleohistological thin sections and CT scans. Results show that during terrestrial locomotion, Indohyus probably had a digitigrade posture and mediolaterally stabilised limbs that functioned mostly in flexion and extension within the parasagittal plane. Quantification of midshaft cross-sectional area for some elements of Indohyus showed an osteosclerotic cortex, a skeletal characteristic associated with aquatic behaviours. Indohyus may represent a critical intermediate in the evolution of the cetacean terrestrial-to-aquatic body plan, as it bears gracile postcranial element proportions similar to a terrestrial artiodactyl but also an incipient form of osteosclerosis compared to pakicetid archaeocetes.     

Analysis of polymorphisms in the major expressed class I locus (B-FIV) of the chicken

 We analyzed the polymorphic nature of eleven alleles expressed by the major class I locus (B-FIV) in chickens. Similar to mammalian class I loci, the nucleotide substitutions with high variability occur in exons 2 and 3 encoding the α1 and α2 domains. However, the nonsynonymous to synonymous ratio of nucleotide substitutions in exon 3 encoding the α helix and β sheets is reversed compared with HLA. The region of exon 3 encoding the α2 helix demonstrates a much lower nonsynonymous to synonymous ratio, suggesting evolutionary selection of a more conserved α2 helix in B-FIV compared with HLA. Amino acid residues with high Wu-Kabat variability are typically located in positions predicted to impact antigen presentation. B-FIV amino acid residues predicted to interact with the CDR1α region of the T-cell receptor (Tcr) demonstrate less variability than in mouse and human class I alleles. The combination of a reduced nonsynonymous to synonymous ratio in exon 3 encoding the α2 helix and the limited variability in CDR1α contact residues is discussed with regard to concerted evolution between a minimal major histocompatibility complex and compaction of Tcr variable gene segments in the chicken. Received: 18 Juli 1997 /  Revised: 21 November 1997     

Selected di- and tetranucleotide microsatellites from chromosomes 7, 12, 14, and Y in various Eurasian populations

Microsatellite polymorphisms of nine Eurasian populations (>1200 chromosomes) were analyzed for the following loci: i) intronic (gt) _n stretches of three T cell receptor (TCR) B loci on chromosome 7 (TCRBV6S1, TCRBV6S3, TCRBV6S7); ii) an intergenic (gt) _n repeat in the region between the TCRDV3 and TCRAJ61 elements on chromosome 14; iii) two tetranucleotide simple repeats (D12S66, D12S67), not linked to known genes on chromosome 12; iv) a Y-chromosomal (gata) _n polymorphism (DYS19). In general, allele frequencies and heterozygosity rates were similar, but specific alleles were missing in one or more populations. Distinct DYS19 alleles predominated in particular cohorts. Different allele frequencies were observed for the TCR loci in European and Asian populations. Tetranucleotide polymorphisms were distributed normally, whereas TCR alleles displayed bimodal frequency profiles. For TCRBV6S1 and TCRBV6S7, this profile reflects a diallelic protein polymorphism that correlates exactly with the length of the intronic repeats.     

Creation of a SINE enriched library for the isolation of polymorphic (AGC)n microsatellite markers in the bovine genome

Trinucleotide (AGC)_n microsatellites are found as 3′ tails of the artiodactyl short interspersed nuclear element (SINE) A-dimer. We describe a polymerase chain reaction (PCR)-based method for the construction of a plasmid library enriched for SINE (AGC)_n microsatellites. By amplifying Sau3AI inserts with a conserved SINE primer and a flanking vector primer, a 35-fold enrichment of (AGC)_n microsatellites over a conventional genomic library was obtained. The SINE primer was used for both sequencing of AGC-containing inserts and analysis of polymorphism. Twenty-three unique reverse primers were synthesized and used on bovine genomic DNA, 21 producing PCR products of expected size. Five polymorphic (AGC)_n microsatellites with 2–4 alleles each were characterized. Allele sizes differed by a 3 bp motif and lacked the stutter bands associated with dinucleotide repeats. A tendency of increased polymorphism for longer AGC repeat arrays was observed. High stringency selection for positive clones containing eight or more AGC repeats can thus facilitate the isolation of polymorphic (AGC)_n microsatellites, Enrichment for (AGC), microsatellites by SINE-vector PCR can be applied to other bovidae species, such as sheep or goat, containing the artiodactyl SINE elements.     

Identification of the human homolog of the imprinted mouse Air non-coding RNA

Genomic imprinting is widely conserved amongst placental mammals. Imprinted expression of IGF2R, however, differs between mice and humans. In mice, Igf2r imprinted expression is seen in all fetal and adult tissues. In humans, adult tissues lack IGF2R imprinted expression, but it is found in fetal tissues and Wilms' tumors where it is polymorphic and only seen in a small proportion of tested samples. Mouse Igf2r imprinted expression is controlled by the Air (Airn) ncRNA whose promoter lies in an intronic maternally-methylated CpG island. The human IGF2R gene carries a homologous intronic maternally-methylated CpG island of unknown function. Here, we use transfection and transgenic studies to show that the human IGF2R intronic CpG island is a ncRNA promoter. We also identify the same ncRNA at the endogenous human locus in 16–40% of Wilms' tumors. Thus, the human IGF2R gene shows evolutionary conservation of key features that control imprinted expression in the mouse.     

Conservation genetics of the endangered endemic Sambucus palmensis Link (Sambucaceae) from the Canary Islands

Five polymorphic microsatellites (simple sequence repeat; SSR) markers were used to estimate the levels of genetic variation within and among natural populations from different islands of the endangered endemic from the Canary Islands Sambucus palmensis Link (Sambucaceae). Genetic data were used to infer potential evolutionary processes that could have led to present genetic differentiation among islands. The levels of genetic variability of S. palmensis were considerably high; proportion of polymorphic loci (P = 100%), mean number of alleles per locus (A = 6.8), average expected heterozygosity (He = 0.499). In spite of its small population size and endemic character, 58 different multilocus genotypes were detected within the 165 individuals analyzed. All samples located in different islands always presented different multilocus genotypes. Principal Coordinates Analysis, genetic differentiation analysis (F _ST and G _ST ′) and Bayesian Cluster Analysis revealed significant genetic differences among populations located in different islands. However, this genetic differentiation was not recorded among Tenerife and La Gomera populations, possibly revealing the uncontrolled transfer of material between both islands. AMOVA analysis attributed 77% of the variance to differences within populations, whereas 8% was distributed between islands. The levels of genetic differentiation observed among populations, and the genetic diversity distribution within populations in S. palmensis, indicate that management should aim to conserve as many of the small populations as possible. Concentrating conservation efforts only on the few large populations would result in the likelihood of loss of genetic variability for the species.     

Typing of artiodactyl MHC-DRB genes with the help of intronic simple repeated DNA sequences

An efficient oligonucleotide typing method for the highly polymorphic MHC-DRB genes is described for artiodactyls like cattle, sheep and goat. By means of the polymerase chain reaction, the second exon of MHC-DRB is amplified as well as part of the adjacent intron containing a mixed simple repeat sequence. Using this primer combination we were able to amplify the MHC-DRB exons 2 and adjacent introns from all of the investigated 10 species of the family of Bovidae and giraffes. Therefore, the DRB genes of novel artiodactyl species can also be readily studied. Oligonucleotide probes specific for the polymorphisms of ungulate DRB genes are used with which sequences differing in at least one single base can be distinguished. Exonic polymorphism was found to be correlated with the allele lengths and the patterns of the repeat structures. Hence oligonucleotide probes specific for different simple repeats and polymorphic positions serve also for typing across species barriers. The strict correlation of sequence length and exonic polymorphism permits a preselection of specific oligonucleotides for hybridization. Thus more than 20 alleles can already be differentiated from each of the three species.     

Artiodactyl retroposons: association with microsatellites and use in SINEmorph detection by PCR.

During a search of polymorphic microsatellites for bovine genome mapping, we found that microsatellites often occur as tails of artiodactyl C-A retroposon elements. In this element, C (85bp) is a tRNA derivative, while A (117bp) is of unknown origin. The A element also occurs as dimer element with a connecting 27bp linker sequence comprising hexanucleotide CACTTT repeats. In 10 clones (45% of those selected deliberately for dinucleotide repeats), the microsatellite motif is associated with the C-A retroposon. In 50% of 44 database artiodactyl C-A sequences, the element also has a microsatellite tail. The microsatellite is usually a simple (CA)n repeat, but in some cases it is an apparent derivative of the linker sequence CACTTT. All but one of 33 database dimer elements have trinucleotide repeat tails (AGC)n, n = 1-9. Microsatellites, retroposons, and their truncated versions (C and/or A) often occur as clusters. We derived the consensus sequence (202bp) of the C-A element, and designed four primers for inter-SINE amplification with the aim of finding SINEmorph polymorphisms. The method is potentially powerful for rapidly producing polymorphic markers for artiodactyl genome mapping.     

Genetic diversity across natural populations of <Emphasis Type="Italic">Dendrobium officinale</Emphasis>, the endangered medicinal herb endemic to China,revealed by ISSR and RAPD markers

Dendrobium officinale is a rare and endangered herb with special habitats and endemic to China. Genetic diversity was examined within and among nine natural populations using inter-simple sequence repeat (ISSR) and random amplified polymorphic (RAPD) for conservation. Both molecular markers revealed a high percentage (>89%) of polymorphic bands and ISSR markers detected more diversity than RAPD markers. Analysis of molecular variance (AMOVA) revealed that 78.84% (ISSR) and 78.88% (RAPD) of variability was partitioned among individuals within populations. This genetic structure was probably due to severe genetic drift resulting from habitat fragmentation and human overexploitation since 1950s. Moreover, there is a lack of significant association between genetic and geographic distances (r = 0.276; p > 0.05) in the populations of D. officinale. From the conservation point of view, populations GL, GS and GSD with higher genetic diversity should be protected firstly to maintain the species potential for evolutionary change and population YG with lower diversity but representing a novel evolutionary unit should also be paid more attention to during D. officinale conservation practice. Published in Russian in Genetika, 2009, Vol. 45, No. 3, pp. 375–382. The article is published in the original.     

Selection and regeneration of toxin-insensitive plants from tissue cultures of oats (Avena sativa) susceptible to Helminthosporium victoriae

Summary Insensitivity to the pathotoxin victorin, which is produced by the fungus Helminthosporium victoriae (Meehan and Murphy), was selected in tissue cultures of oat (Avena sativa L.) lines heterozygous for the dominant sensitive allele Vb. The Vb allele imparts both susceptibility to H. victoriae and resistance to several races of oat crown rust (Puccinia coronata var. avenae, Fraser and E. Led.). None of 84 homozygous Vb Vb oat calli survived when grown on victorin-containing medium. Among 175 calli of heterozygous Vb vb cultures grown on toxin-containing medium, 16 representing 13 separate embryo-derived culture lines produced surviving callus sectors or shoots. Based on leaf bioassays of plants regenerated after toxin selection, nine culture lines gave toxin-insensitive plants and two gave plants showing the toxin sensitivity of the parent. Two selected lines failed to regenerate. Plants regenerated from 30 culture lines which had never been exposed to toxin-containing selection medium were all toxin sensitive. The toxin insensitivity of the regenerants from the toxin-selected culture lines was heritable since progeny of these plants were all insensitive. The toxin-insensitive selected lines all were found to have coincidentally lost the Vb crown rust resistance of the original line. In cytological analysis of meiotic cells of regenerants from the selected cultures, no chromosomal deficiency was found which could be associated with, and thus account for, the loss of sensitivity to the toxin. Somatic recombination and mutation to vb vb are other possible origins of toxin insensitivity in the selections. The victorin selection demonstrates that specific resistance can be selected in tissue cultures of oats. It also provides a highly sensitive scheme to test effects of culture conditions and chemical agents on induction of genetic and chromosomal changes in tissue cultures.Joint contribution of USDA-ARS and the Minnesota and Florida Agric. Exp. Stns. Paper No. 14121, Scientific Journal Series, Minnesota Agric. Exp. Stn     

Coding versus intron variability: extremely polymorphic HLA-DRB1 exons are flanked by specific composite microsatellites, even in distant populations

Although microsatellite typing is the dominant method in genome research and indirect gene diagnosis, precise relationships of exonic and adjacent simple repeat polymorphisms are not known. We investigated exon 2 sequences of HLA-DRB1 genes and their neighbouring (GT)_n(GA)_m repeats including the intervening single copy spacer. DRB1 is the most polymorphic protein-coding locus in man and all vertebrates investigated. The entire DRB1 variability exists in exon 2. DRB1 genes in different haplotype groups (DR1, DR51, DR52, DR8 and DR53) are accompanied by characteristic modifications of the (GT)_n(GA)_m block (3′ to group-specific single copy spacers). Among more than 520 alleles analysed, > 100 different types of microsatellites were observed. The perfect (GT)_n and (GA)_m blocks vary in length and may be partly ‘degenerated’, mostly in a subgroup-specific manner. Interestingly, the extent of microsatellite diversity varies in given DRB1 alleles. While the microsatellites of the DR7, DR9 alleles and in the DR1 group are virtually invariant, in DR4 and DR13, in particular, simple repeats appear hypervariable with at least 15 or 17 different length alleles, respectively. Comparing Caucasians, Bushmen and South American Indians, the microsatellite variation in identical DRB1 alleles (e.g. DRB1*0102, 03 011, 1302) is smaller than within any of the DR groups in Caucasians. Taken together, extremely polymorphic DRB1 exons evolve in concert with certain variants of an exceptionally well-preserved microsatellite. Received: 8 October 1996     

A proposal for standardization in forensic equine DNA typing: allele nomenclature for 17 equine‐specific STR loci

In this study, a proposal is presented for the allele nomenclature of 17 polymorphic STR loci (AHT4, AHT5, ASB2, ASB17, ASB23, CA425, HMS1, HMS2, HMS3, HMS6, HMS7, HTG4, HTG6, HTG7, HTG10, LEX3 and VHL20) for equine genotyping (Equus caballus). The nomenclature is based on sequence data of the polymorphic region of the STR loci as recommended by the DNA commission of the International Society for Forensic Genetics for human DNA typing. For each STR locus, several alleles were selected and animals homozygous for those alleles were subjected to sequence analysis. The alleles of the 17 STR loci consisted either of simple (10), compound (6) or complex repeat patterns (1). Only a limited number of alleles with the same fragment size showed different repeat structures. The allele designation described here was based on the number of repeats, including all variable regions within the amplified fragment.     

Analysis of molecular genetic diversity and population structure in Amaranthus germplasm using SSR markers

We assessed the molecular genetic diversity and population structure of Amaranthus species accessions using 11 simple sequence repeat markers. A total of 122 alleles were detected, and the number of alleles per marker (N_A) ranged from 6 to 21 with an average of 11.1 alleles. The frequency of major alleles per locus ranged from 0.148 to 0.695, with an average value of 0.496 per marker. The overall polymorphic information content values were 0.436–0.898, with an average value of 0.657. The observed heterozygosity (H_O) and expected heterozygosity (H_E) ranged from 0.056 to 0.876 and from 0.480 to 0.907, with average values of 0.287 and 0.698, respectively. The average H_O (0.240) was lower than the H_E and gene flow (Nm), and showed substantial genetic variability among all populations of amaranth accessions. The sample groupings did not strictly follow the geographic affiliations of the accessions. A similar pattern was obtained using model-based structure analysis without grouping by species type. Knowledge of the genetic diversity and population structure of amaranth can be used to select representative genotypes and manage Amaranthus germplasm breeding programs.     

Microsatellite analysis of genetic diversity in the Chinese alligator (<Emphasis Type="Italic">Alligator sinensis</Emphasis>) Changxing captive population

Chinese alligator (Alligator sinensis) is a critically endangered species endemic to China. In this study, the extent of genetic variation in the captive alligators of the Changxing Reserve Center was investigated using microsatellite markers derived from American alligators. Out of 22 loci employed, 21 were successfully amplified in the Chinese alligator. Sequence analysis showed loci in American alligators had a bigger average size than that of the Chinese alligators and the longest allele of an individual locus almost always existed in the species with longer stretch of repeat units. Eight of the 22 loci were found to be polymorphic with a total of 26 alleles present among 32 animals scored, yielding an average of 3.25 alleles per polymorphic locus. The expected heterozygosity (H _E) ranged at a moderate level from 0.4385 to 0.7163 in this population. Compared to that in the American alligators, a lower level of microsatellite diversity existed in the Changxing population as revealed by about 46% fewer alleles per locus and smaller H _E at the homologous loci. The average exclusion power and the ability to detect shared genotypes and multiple paternity were evaluated for those markers. Results suggested that when the polymorphic loci were combined, they could be sensitive markers in genetic diversity study and relatedness inference within the Chinese alligator populations. The level of genetic diversity present in the current Changxing population indicated an important resource to complement reintroductions based on the individuals from the other population. In addition, the microsatellite markers and their associated diversity characterized in this population could be utilized to further investigate the genetic status of this species.